Need help trying to figure out network drops

Hello! I'm a medium knowledge level Sysadmin working for a small company of about 30 users or so. After coming on board, the company already had some devices in place and I've also installed some devices. At this time, we're experiencing network drops that I'm trying to understand why they're happening and what I can do to fix them.

To give some background on the network infrastructure: Modem -> Sophos XG 430 Firewall ->

LGS124P Switch (Unmanaged) -> Domain Controller (DNS server as well)

LGS124P Switch (Unmanaged) -> Sophos 100C Access point

LGS124P Switch (Unmanaged) -> Netgear Ac1700 Router (acting as an access point)

The Netgear router is acting as an AP because we origianlly had to 100C Access Points and one of the died, and I had to make a quick fix, and used that to give the second half of the office wifi.

Onto information on the actual issue. Periodically, throughout the day, the network will go down. The drops happen for about 45 seconds then everything is fine. I've noticed this before so from the Domain Controller, I have 5 ping tests writing to text files to show me what is going on. I have:

• Ping to Firewall
• Ping to Access Point (Sophos AP)
• Ping to Router acting as AP
• Ping to self
• Ping to 8.8.8.8

During the last "outage", the ping to Firewall returned "Request timed out". The ping to AP was fine, no dropped packets. The ping to router acting as AP returned "Reply from 192.168.254.3: Destination host unreachable.". Ping to 8.8.8.8 returned "Reply from 192.168.254.3: Destination host unreachable." (192.168.254.3 is IP of DC/DNS server).

So my first question is: What better tools are there for figuring out what the hell is happening? One problem i'm having is that Ping doesn't leave a timestamp, so i can't properly determine if these are actually happening at the same time.

Second: My best guess as to what's happening right now is that the AC1700 is being overloaded or is dropping connections. But i'm not sure because when these "blips" happen, the whole office is effected.

Any help at this point would be appreciated. Thank you.